44,140 research outputs found
The first version Buffered Large Analog Bandwidth (BLAB1) ASIC for high luminosity collider and extensive radio neutrino detectors
Future detectors for high luminosity particle identification and ultra high
energy neutrino observation would benefit from a digitizer capable of recording
sensor elements with high analog bandwidth and large record depth, in a
cost-effective, compact and low-power way. A first version of the Buffered
Large Analog Bandwidth (BLAB1) ASIC has been designed based upon the lessons
learned from the development of the Large Analog Bandwidth Recorder and
Digitizer with Ordered Readout (LABRADOR) ASIC. While this LABRADOR ASIC has
been very successful and forms the basis of a generation of new, large-scale
radio neutrino detectors, its limited sampling depth is a major drawback. A
prototype has been designed and fabricated with 65k deep sampling at
multi-GSa/s operation. We present test results and directions for future
evolution of this sampling technique.Comment: 15 pages, 26 figures; revised, accepted for publication in NIM
Polycyclic aromatic hydrocarbons (PAHs) in air and vegetation: case study at three selected toll stations along North South Expressway in Johor, Malaysia
Polycyclic aromatic hydrocarbons (PAHs) from vehicular emission are products of
the incomplete combustion of organic fuel, and are usually attached to the particulate
matter from the emission and can caused pollution and hazard to human health due to
its carcinogenic, mutagenic and teratogenic characteristics. The objective of this
study is i) to determine the concentration PAHs in the air of sampling area, ii) to
determine the concentration PAHs in vegetation, iii) to determine the relationship of
concentration of PAHs in plants and air of sampling area and iv) to study the
different composition of PAHs in different species of plants to determine the
potential biomonitoring agent. The study is carried out at three toll stations along
PLUS’ North-South Expressway in Johor. Air sample and plant leaves sample
collected were extracted with ultrasonic agitation in dichloromethane and
fractionated according to polarity before submitted to gas chromatography – mass
spectrometry analysis to determine the concentration of the PAHs compounds.
Spearman’s rank correlation test was carried out using SPSS to determine the
correlation between concentration of PAHs in air and plant leaves sample. Seven
PAHs were identified and quantified in the atmospheric sample and plant leaves
sample. Those PAHs were acenaphtylene (ACN), phenanthrene (PHE), fluorene
(FL), pyrene (PY), chrysene (CHR), benzo[a]anthracene (BaA), and benzo[a]pyrene
(BaP). Significant correlation at 0.05 level (2-tailed) was observed in samples
of Ficus microcarpa, Cordyline fruticosa, Hibiscus spp., and Ixora coccinea with the
value 0.622, 0.643, 0.680 and 0.608 respectively. The positive correlation shows that
the plants have capabilities to absorb organic pollutants from the environment. Based
from this research, the most suitable species to be introduced into the environment as
a biomonitoring agent and to be further studied as a medium for low and medium
level pollution bioremediation is Ficus microcarpa, Cordyline fruticosa, and Ixora
coccine
Progress of analog-hybrid computation
Review of fast analog/hybrid computer systems, integrated operational amplifiers, electronic mode-control switches, digital attenuators, and packaging technique
Analog-to-digital conversion techniques for precision photometry
Three types of analog-to-digital converters are described: parallel, successive-approximation, and integrating. The functioning of comparators and sample-and-hold amplifiers is explained. Differential and integral linearity are defined, and good and bad examples are illustrated. The applicability and relative advantages of the three types of converters for precision astronomical photometric measurements are discussed. For most measurements, integral linearity is more important than differential linearity. Successive-approximation converters should be used with multielement solid state detectors because of their high speed, but dual slope integrating converters may be superior for use with single element solid state detectors where speed of digitization is not a factor. In all cases, the input signal should be tailored so that they occupy the upper part of the converter's dynamic range; this can be achieved by providing adjustable gain, or better by varying the integration time of the observation if possible
Electronic circuits and systems: A compilation
Technological information is presented electronic circuits and systems which have potential utility outside the aerospace community. Topics discussed include circuit components such as filters, converters, and integrators, circuits designed for use with specific equipment or systems, and circuits designed primarily for use with optical equipment or displays
Comparator Design in Sensors for Environmental Monitoring
This paper presents circuit design considerations of comparator in analog-to-digital converters (ADC) applied for a portable, low-cost and high performance nano-sensor chip which can be applied to detect the airborne magnetite pollution nano particulate matter (PM) for environmental monitoring. High-resolution ADC plays a vital important role in high perfor-mance nano-sensor, while high-resolution comparator is a key component in ADC. In this work, some important design issues related to comparators in analog-to-digital converters (ADCs) are discussed, simulation results show that the resolution of the comparator proposed can achieve 5µV , and it is appropriate for high-resolution application
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